There is something fundamentally ambiguous about your probability argument. You feel as if the conditions for life are very improbable because they are totally tuned to exactly life's needs. But this is a position that can only be borne of a narrow outlook on probability and chance, and especially on evolution.
If the conditions had been any different, then a different form of life would have arisen, evolutionarily fit for that environment, that would proceed to conclude that its own environment was so improbable that it could only have come from God. This is the case of any other set of conditions in the universe. Any set of conditions that gave rise to any sort of life through evolution and natural selection would seem completely improbable to that life, if it gained an ability to ponder such things.
You're saying what someone would say when he or she saw a configurations of wildflowers on a hill that spelled out a word, namely, that that is completely improbable and must have been made by someone, while failing to realize that
any other formation of flowers would be equally improbable.